How Do You Unlock More Harvest Slots in MHW?

To Harvest in MHW you will need to find a monster that is weak to traps, and then set said traps around the monster. After the trap has been set, you will need to wait for the monster to step into the trap which will then put it to sleep/paralysis/stun.

You can then approach the monster and press circle/B to harvest from it. .

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You can increase the number of harvest slots you have by completing certain optional quests, which will give you 1-2 extra slots. The first such quest is called “The Bestial” and is available after completing the 6* quest “The White Winds of the New World”.

The second quest is called “Wild Things” and is available after completing the 8* quest “Into the Bowels of the Beast”. Both quests must be completed on HR difficulty or higher.